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JIGGER AND JOLLEY WORK (Pottery, for artists)
CHAPTER V JIGGER AND JOLLEY WORK "Earth I am, et is most trwe, desdan me not, for so ar you." From an old platter. DISHES, platters, and to some extent bowls, are usually made on a Jigger and Jolley. The jigger has a revolving head, fitted to receive moulds. The jolley has a pivoted arm to which different profiles may be clamped. In factories these things are com- plicated and go by power, but in a studio where the output of platters and dishes is likely to be limited something simple will do. Where the wheel is 'strong, well-hung, and fitted with a removable head, a contrivance as shown at Fig. 21 can be fitted by any carpenter, that should serve all purposes. The vertical supports of the jolley arm should be quite rigid. The arm itself must so pivot that the face of any profile screwed onto it will cross the head of the jigger, or wheel if one be used, through the centre. In other words, the cutting profile must form a diagonal of the circular head. Then, too, it must be hung at. a height sufficient to allow a fairly thick block of plaster being used for a mould. When making these moulds, the slotted wheel 51 MAKING A DI/H FIG. 21 head or the jigger head is removed and soaped or oiled. Then a circular block of plaster is cast to fit. This may be done with the aid of a roll of lin- oleum, much in the way described in casting. The paper cone will, of course, be replaced by the wheel head, bedded face up in clay. This plaster block has to be moulded to the exact size of the dish or plaque required. To do this a profile of zinc is necessary. The true section of the dish is drawn full size, and profiles giving one half of the back and front are traced on a stout sheet of zinc. The zinc is roughly cut to shape with shears and then finished with a file to a chisel edge (see cut). The two profiles are then firmly backed with shaped wooden forms, slotted to screw onto the arm of the jolley. The PROFILE IN P-Q/1T10N ABC3W PLATE MOMCD FIG. 22 profile giving the /ace of the plaque is securely ad- justed in a horizontal position, the inner point, giving the centre of the platter, being exactly over the centre of the jigger head. The plaster block, which should be turned down before it sets hard, is shipped back into position, the jigger revolved and the profile gradually pressed down until the true section is obtained, i.e. when the profile is exactly horizontal again. The mould is now removed, trimmed at the sides if necessary, and set apart to dry. It is then ready to use. The mould is slipped into position and revolved to insure even rotation. Then the profile giving the back of the platter screwed onto the arm and both adjusted until the stop allows the profile to rest at just that distance from the mould required by the thickness of the platter. (Fig. 22.) 54 The arm is then swung clear of the mould, which is well sponged with water to receive the clay. This is carefully wedged and then rolled out or batted flat on a piece of leather until it is a little thicker than the thickest part of the platter (see Fig. 23). The slab so made is smoothed with a palette knife, taken up, leather and all, slapped onto the mould, clay side down, and the leather re- moved. The clay is now well dabbed down with a wet sponge or dabber, to take out all wrinkles, pressed firmly onto the mould and the waste cut off. Now the jigger or head is set spinning, the jolley pulled over it, and the profile gently pressed into the clay. Water is used freely to prevent the profile sticking, and as it becomes clogged the clay is removed. The turning is continued until the profile comes to a stop on the rest. Holes that may appear should be filled up before the finish, at which time the surface should present a smooth unscratched appear- ance. The shape is allowed to dry on the mould until tough enough to be slipped face down onto a per- fectly flat slab dusted with fine sand or flint to pre- CUTTINGEDCE OFPKOEiLE FIG. 28 55 vent sticking. In this position it is left to dry, when the edges are nicely trimmed with fine sandpaper. For bowls the process is similar, but the mould here gives the outside and the profile the inside as in cut. (Fig. 24.) If made on the outside, they split before they can be removed. With small bowls the clay is wedged and a lump pressed into the mould by hand. With large bowls requiring a deep foot this must be turned separately and stuck on after the bowl is removed from the mould. Where a jigger and jolley is not available, plates and bowls may be duplicated as follows : Place the plate bottom up on a well-soaped surface or a piece of glass. Should the plate not lie quite flat, caulk the apertures with clay, then all round and distant one and one half inches from the rim, build clay walls, or fix a containing band of linoleum, of sufficient height to allow plaster being poured in an inch and a half above the base or foot of the model. Mix fairly stiff plaster and pour in. Let it set, and then remove walls and the model. This gives a mould of the reverse of the plate or bowl. The mould is BOWL FIG. 24 56 PLATE -MOULDIP TO GIVE BACK- Fio. 25 thoroughly dried before using and then sponged with clean water. Clay of the desired thickness is then rolled out as described and applied to the mould and dabbed flat with a sponge or dabber. The finish is imparted with the fingers and the surplus at edges trimmed with a knife. When PLASTER MOULP. To GIVE te^&a^. TACt or PLATE. .&OWJ3 FIG. 26 tough, the press is slipped out and reversed to dry on a piece of sanded glass. Where there is a rim to the plate or bowl, this should be filled in cleanly with clay before the whole is pressed. It is of course impossible to mould thus bowls that possess a deep or undercut foot. 58 E^ypt. B.